Fig. 1

Sequence of the neurophysiological pre-investigations (warm detection threshold (WDT), cold detection threshold (CDT), heat pain threshold (HPT), electroneurography (ENG)) and of the fMRI experiment (rest (R) alternating with the conditions “CT touch” (CT), “heat pain” (HP) and “heat pain with CT touch” (HP + CT), which were performed in randomized order) is demonstrated for both groups. The dark grey scaled boxes indicate the rating periods of pain intensity (on NRS), onsets are marked by black arrows. The big grey box demonstrates the tests performed in the scanner room